Do these 3 things before closing this tab:
1Scan for outdated or missing drivers - takes under a minute2Repair Windows errors before they cause bigger problems3Fix the driver behind crashes, sound loss and screen glitchesA 2024 study documented California ground squirrels pursuing, killing, and eating California voles at Briones Regional Park in Contra Costa County. Researchers recorded 74 vole-hunting and/or consumption events, including 31 active hunts and 17 successful captures. These observations show striking behavioral flexibility at one site during one summer—not that all California ground squirrels hunt, or that the species has permanently changed its diet.
What the researchers observed
Researchers studied California ground squirrels at a 9,596-square-meter area in Briones Regional Park as part of a long-running behavioral study. From June 10 to July 30, 2024, they observed the animals during trapping days and 16 formal weekday sessions. Three observer groups watched separate parts of the site from at least 20 meters away. Formal observations totaled 146 hours.
| # | Preview | Product | Price | |
|---|---|---|---|---|
| 1 |
|
Perfect Planet | $8.28 | Buy on Amazon |
| 2 |
|
Seven Worlds, One Planet | $14.54 | Buy on Amazon |
| 3 |
|
The Planet Earth Collection (DVD) | $10.05 | Buy on Amazon |
| 4 |
|
Ken Burns: The National Parks: America's Best Idea DVD | $30.98 | Buy on Amazon |
| 5 |
|
National Geographic: Great Migrations | $5.98 | Buy on Amazon |
The study recorded 74 vole-hunting and/or consumption events over 18 fieldwork days. Sixty-five events occurred on formal observation days, and the behavior was seen on 13 of the 16 formal observation days. Incidents peaked during the first two weeks of July.
| Measure | Study finding | How to interpret it |
|---|---|---|
| Vole-related events | 74 | Events involving hunting and/or consumption, not a count of individual squirrels |
| Active hunts | 31 of 74 (42%) | Active pursuit made up 42% of the recorded vole-related events |
| Successful captures and kills | 17 of 31 attempts (55%) | Success among observed hunting attempts, not all hunts by the population |
| Formal observation time | 146 hours | Across the 16 formal weekday sessions |
These counts describe what researchers observed; they are not estimates of how often an individual squirrel hunts or how common hunting is across the species.
Quick wins for a faster PC:
Scan for outdated or missing drivers - takes under a minuteDriver Scan →Clear out junk files and repair common Windows errorsFree Scan →#1 Best Overall
How the study defines hunting
The paper defines active hunting as active pursuit. That distinction matters: the 31 active hunts were a subset of the 74 recorded vole-related events, which also included consumption without a recorded active pursuit. The study reports that squirrels captured and killed voles in 17 of the 31 observed hunting attempts.
How many squirrels were involved?
Researchers could assign 51 of the 74 events to an identifiable squirrel, involving 27 distinct individuals. The statistical analyses included 26 identified squirrels that had been present on at least three formal observation days. The researchers found no apparent age or sex bias in participation or hunting success.
Hunting appeared largely solitary. The authors interpreted two simultaneous attacks on one vole as likely coincidental rather than cooperative hunting.
Why were the squirrels hunting voles?
The observations took place in a year when California vole sightings reported to iNaturalist peaked at roughly seven times the preceding ten-year average, according to the Smith et al. study in the Journal of Ethology. This is a comparison of reported sightings, not a direct count of voles.
Rank #2
Researchers did not measure vole density at the park, so the study cannot prove that a local vole increase caused the hunting. The timing and observations are consistent with the possibility that squirrels responded to temporarily available prey, but causation remains unestablished.
The study reported that vole interactions occurred more often in areas with high ground-squirrel density, especially open areas with little ground or tree cover, rather than concentrating around vole burrows. The authors note that voles also used abandoned squirrel burrows as a possible explanation for this pattern.
Did squirrels eat meat “for the first time”?
No—not if that means no squirrel had ever eaten animal tissue before. The paper discusses earlier reports of animal consumption by California ground squirrels, as well as evidence of vertebrate predation in other squirrel species.
The authors describe the 2024 observations as the first evidence of widespread hunting of adult mammalian prey by California ground squirrels in nature. That is a narrower claim than saying this was the first time any squirrel had eaten meat. The notable finding is repeated active pursuit of live mammal prey by this species in a natural setting.
Are California ground squirrels becoming carnivores?
The study does not show that California ground squirrels have become specialized carnivores or permanently changed their diet. It covers one site and one field season, during a year with unusually high vole-sighting reports.
The authors suggest that “opportunistic omnivore” may describe the species better than “granivore.” This is an interpretation of dietary flexibility, not proof that every population regularly eats meat.
The study cannot establish how widespread the behavior is across California, whether it recurs in ordinary vole years, whether hunting is innate or learned, or whether it affects squirrel reproduction or survival.
What the study cannot tell us
- Prevalence elsewhere: The observations came from one park; they do not establish how common the behavior is across the species’ range.
- Frequency in other years: The study does not show whether hunting recurs when vole reports are not unusually high.
- Cause: Researchers did not directly measure vole density at the field site or experimentally test what prompted the behavior.
- Learning: The observations do not determine whether hunting is innate, learned, or both.
- Ecological effects: Effects on vole populations, disease transmission, and grassland ecology remain questions for future research.
What the study really shows
Smith et al., in the Journal of Ethology, documented 74 vole-related events at Briones Regional Park in 2024. Thirty-one involved active pursuit, and 17 of those observed hunting attempts ended in capture and killing. The findings provide evidence of repeated mammal hunting by California ground squirrels at this site, not a population-wide or statewide prevalence estimate.
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
The authors interpret the observations as evidence of behavioral flexibility and possible opportunistic omnivory. Whether the behavior occurs elsewhere, returns in future vole pulses, or has measurable ecological effects remains unknown.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.FAQ
Did California ground squirrels really hunt voles?
Yes. The 2024 study documented active pursuit of California voles by California ground squirrels at Briones Regional Park in Contra Costa County.
How many squirrels hunted voles?
Researchers assigned 51 of the 74 vole-related events to identifiable squirrels, involving 27 distinct individuals. That does not mean all 27 hunted; the study does not give a population-wide count of hunters.
What does 42% mean in the study?
It means 31 of the 74 recorded vole-related events involved active pursuit. It does not mean that 42% of squirrels, or 42% of the species, hunted voles.
Best Value
Why were squirrels eating voles in 2024?
Vole sightings reported to iNaturalist peaked at roughly seven times the preceding ten-year average. The researchers did not directly measure vole density at the park, so this timing supports a possible link but does not prove the cause.
Does this mean ground squirrels are carnivores now?
No. The study documented hunting at one site in one summer. The authors suggest “opportunistic omnivore” as a way to describe dietary flexibility, but they did not establish a permanent dietary change.
Do ground squirrels normally eat meat?
California ground squirrels are commonly described as seed- and plant-eaters, and the paper notes earlier isolated reports of animal consumption. The 2024 study documents repeated hunting of adult mammalian prey in nature; it does not show how often this occurs elsewhere.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
Recommended Free Tools
